there is a problem with the color black, but only in this special workflow as follows:
open a new document in RGB > convert it or change the color mode to CMYK > define a new color with 0,0,0,100 > draw a form > reselect the form and check the color ... the 100K black has changed to a 4-channel black.
if you start right away with a new CMYK-document, everything is fine and you will always get you 0,0,0,100-black-color, but whenever you start with a RGB-document the whole black-color-thing is bugged forever! even if you save the "from rgb to cmyk converted" document, close it an reopen it: you still have the problem.
my guess is, the document itself is in cmyk, but the colorpicker and everything around that is still working in rgb-mode and is converting every color back to cmyk. in most cases it will not change any color, but black ist completely different, especially with black in 0,0,0,100.
there is a problem with the color black, but only in this special workflow as follows:
open a new document in RGB > convert it or change the color mode to CMYK > define a new color with 0,0,0,100 > draw a form > reselect the form and check the color ... the 100K black has changed to a 4-channel black.
if you start right away with a new CMYK-document, everything is fine and you will always get you 0,0,0,100-black-color, but whenever you start with a RGB-document the whole black-color-thing is bugged forever! even if you save the "from rgb to cmyk converted" document, close it an reopen it: you still have the problem.
my guess is, the document itself is in cmyk, but the colorpicker and everything around that is still working in rgb-mode and is converting every color back to cmyk. in most cases it will not change any color, but black ist completely different, especially with black in 0,0,0,100.
(win 10, illustrator 25.2.3 (64 bit))